Linear stopper

ABSTRACT

A roller guide device including a first guide member that is provided with an arcuate guide surface, a second guide member that is provided with an arcuate guide surface which is in opposition to the arcuate guide surface of the first guide member and which has a radius of curvature larger than that of the arcuate guide surface of the first guide member, and rollers that are interposed in a freely rollable manner between the arcuate guide surface of the first guide member, and the arcuate guide surface of the second guide member.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.13/519,197, filed Oct. 18, 2012, which was the National Stage ofinternational Application No. PCT/JP2010/073800, filed Dec. 28, 2010,and claims the benefit under 35 USC §119(a)-(d) of Japanese PatentApplication Nos. 2009-298909 and 2010-257847 filed Dec. 28, 2009 andNov. 18, 2010, respectively, the entireties of which are incorporatedherein by reference.

FIELD OF THE INVENTION

The present invention relates to a linear stopper which is mounted on anarbitrary position of a guide member extending in a rectilinear manneror in a curved line manner, and which serves to restrict the movement ofan object guided by means of a guide member.

BACKGROUND OF THE INVENTION

Such a kind of conventional stopper is constructed such that a stoppermember is pushed by a spring force of a spring so that it is fixed by africtional force. However, the force of a spring is weak. Accordingly,there has been known a stopper which is controlled by air pressure,etc., but this stopper is large in size and complicated in control aswell. Here, note that as a similar technique, there is one as describedin Japanese Patent Application Laid-Open No. 2009-006458, for example.

SUMMARY OF THE INVENTION

The present invention has been made so as to solve the problems of theconventional techniques as referred to above, and the object of thepresent invention is to provide a simple linear stopper which is capableof stopping the movement of an object in a reliable manner with a simplestructure.

In order to achieve the above-mentioned object, the present inventioncomprises: a stopper body that is adapted to be detachably mounted on aguide member extending in a linear manner so as to guide an object forreciprocating movement, and has an inclined surface formed thereon, witha wedge-like space being constructed between the inclined surface and asurface of the guide member with a gap decreasing gradually toward oneside of an extending direction of the guide member; rolling elementsthat are arranged in the wedge-like space so as to be rollable therein;and rolling element pressing means that presses the rolling elements ina direction to bite into the wedge-like space, so that the rollingelements are forced into pressure contact with the surface of the guidemember and the inclined surface of the stopper body;

wherein a one-way stopper mechanism is provided which restricts therelative movement of the stopper body with respect to the guide membertoward a side at which the gap in the wedge-like space is large, due toa biting action caused by the rolling contact of the rolling elements inthe wedge-like space, and allows the relative movement of the stopperbody with respect to the guide member toward a side at which the gap inthe wedge-like space is small, due to the sliding contact of the rollingelements in the wedge-like space.

It is preferable that the stopper body be provided with a reaction forcesupport part which is in engagement with the guide member to support areaction force acting on the inclined surface from the rolling elementsupon biting thereof into the wedge-like space at the time of restrictionof the relative movement of the stopper body.

In addition, it is also preferable that rolling element release means beprovided which serves to force the rolling elements arranged in awedge-like space to move in a direction in which the gap in thewedge-like space becomes larger, whereby the stopper body is allowed tomove relative to the guide member toward the side at which the gap inthe wedge-like space is larger.

Moreover, it is also preferable that at least one pair of one-waystopper mechanisms be provided in which the directions of wedge-likespaces with respect to the guide member become mutually opposite to eachother, so that the relative movement of the stopper body with respect tothe guide member in the opposite directions of the reciprocatingmovement thereof can be restricted, and that rolling element releasemeans be provided which serves to force the rolling elements arranged inthe wedge-like space of at least one of the one-way stopper mechanismsto move in a direction in which the gap in the wedge-like space becomeslarger, whereby the stopper body is allowed to move relative to theguide member toward the side at which the gap in the wedge-like space islarger.

According to a linear stopper of the present invention, with a simpleconstruction in which the rolling elements are arranged for free rollingmovement in the wedge-like space formed between the inclined surface ofthe stopper body and the guide member, it is possible to restrict therelative movement of the stopper body with respect to the guide memberdue to the biting action caused by the rolling contact of the rollingelements in the wedge-like space.

In addition, because the rolling elements are in point contact or linecontact, with respect to the movement thereof in an opposed direction,it is possible to release the rolling elements bitten into thewedge-like space therefrom in an easy manner.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1D are views showing the principle construction of a linearstopper of the present invention,

FIGS. 2A and 2B are views showing the schematic construction of a levertype release mechanism which is applied to the linear stopper of thepresent invention.

FIGS. 3A and 3B are views showing the schematic construction of a platetype release mechanism which is applied to the linear stopper of thepresent invention.

FIGS. 4A-4E are views showing the schematic construction of a ring typerelease mechanism which is applied to the linear stopper of the presentinvention.

FIGS. 5A and 5B are views showing the schematic construction of an airtype release mechanism which is applied to the linear stopper of thepresent invention.

FIGS. 6A-6D show the schematic construction of a linear stopperaccording to a first embodiment of the present invention, wherein FIGS.6A and 6B are perspective views, FIG. 6C is a front elevational view,and FIG. 6D is a side elevational view.

FIGS. 7A and 7B show the detailed construction of the linear stopper ofFIG. 6, wherein FIG. 7A is a front elevational cross sectional view, andFIG. 7B is a side elevational view.

FIGS. 8A and 8B show a roller used for the linear stopper of FIG. 7,wherein FIG. 8A is a front elevational view, and FIG. 8B is a sideelevational view.

FIGS. 9A and 9B show an example of a roller guide device using theroller of FIG. 8, wherein FIG. 9A is a front elevational view, and FIG.9B is a side elevational cross sectional view.

FIGS. 10A-10D show the schematic construction of a linear stopperaccording to a second embodiment of the present invention, wherein FIGS.10A and 10B are perspective views, FIG. 10C is a front elevational view,and FIG. 10D is a side elevational view.

FIGS. 11A-1E show the detailed construction of the linear stopper ofFIG. 10, wherein FIG. 11A is a front elevational view, FIG. 11B is aplan cross sectional view, FIG. 11C is a front elevational crosssectional view, FIG. 11D is a side elevational view, and FIG. 11E is abottom view.

FIGS. 12A-12D show the schematic construction of a linear stopperaccording to a third embodiment of the present invention, wherein FIGS.12A and 12B are perspective views, FIG. 12C is a front elevational view,and FIG. 12D is a side elevational view.

FIGS. 13A and 13B show the detailed construction of the linear stopperof FIG. 12, wherein FIG. 13A is a front elevational cross sectionalview, and FIG. 13B is a side elevational view.

FIG. 14 is a view similar to FIG. 13A, but with the exclusion of a guidemember.

FIGS. 15A and 15B show a slide cam of FIG. 13, wherein FIG. 15A is afront elevational view, and FIG. 15B is a development view.

FIGS. 16A-16C show a linear stopper according to a fourth embodiment ofthe present invention, wherein FIG. 16A is a front elevational crosssectional view, FIG. 16B is a cross sectional view along line B-B inFIG. 16A, and FIG. 16C is a cross sectional view along line B-B in FIG.16B.

FIG. 17 is a view showing an exploded construction example of the linearstopper of FIG. 16.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, embodiments of the present invention will be described indetail with reference to the accompanying drawings.

Basic Construction

In FIG. 1, there is shown the basic construction of a linear stopper ofthe present invention.

Specifically, the linear stopper is provided with: a stopper body 1300that is adapted to be detachably mounted on a guide member 1100extending in a linear manner so as to guide an unillustrated object forreciprocating movement, and has a tapered surface 1210, which is aninclined surface constituting a wedge-like space 1200, formed betweenthe inclined surface and a surface of the guide member 1100 with a gapdecreasing gradually toward one side of the extending direction of theguide member 1100; rolling elements 1400 that are arranged in thewedge-like space so as to be rollable therein, and a rolling elementpressing mechanism 1500 that presses the rolling elements 1400 in adirection to bite into the wedge-like space 1200, so that the rollingelements 1400 are forced into pressure contact with the surface of theguide member 1100 and the tapered surface 1210 of the stopper body 1300.

This mechanism constitutes a one-way stopper mechanism that restrictsthe relative movement of the stopper body 1300 with respect to the guidemember 1100 toward a side at which the gap of the wedge-like space 1200is large, due to a biting action caused by the rolling contact of therolling elements 1400 in the wedge-like space 1200, and allows therelative movement of the stopper body 1300 with respect to the guidemember 1100 toward a side at which the gap of the wedge-like space 1200is small, due to the sliding contact of the rolling elements 1400 in thewedge-like space 1200.

Although in the illustrated example, the guide member 1100 is composedof a round shaft having a circular cross section, it may not be theround shaft, but may instead be a shaft of a polygonal shape in crosssection, or may be of a shaft construction with an irregular shape crosssection.

The stopper body 1300 is a block body of a closed cross sectionalstructure which is provided with a through hole 1310 through which theguide member 1100 is inserted, and the stopper body 1300 is provided onan inner periphery of the through hole 1310 with the tapered surface 1which forms the wedge-like space 1200 between itself and an outerperipheral surface of the guide member 1100. In the illustrated example,the through hole 1310 has a circular cross section corresponding to theround shaft.

Although in the illustrated example, the rolling element pressingmechanism 1500 is exemplified as a coil spring, it is not limited tothis, but may be any other thing which can just urge the rollingelements 1400 in a direction to be pushed into the wedge-like space1200.

The rolling elements 1400 are arranged in plurality in a circumferentialdirection of the guide member 1100 at a predetermined interval, and areheld in a freely rotatable manner by means of a retainer 1600 which is arolling element cage. In the illustrated example, balls are exemplifiedas the rolling elements 1400, but the rolling elements are not limitedto balls, but may be rollers. As for the shape of the rollers, rollersin the form of various shapes, such as barrel shaped rollers, hand-drumshaped rollers, etc., can also be applied or used.

In addition, a release mechanism 2000 acting as rolling element releasemeans is provided which serves to force the rolling elements 1400arranged in the wedge-like space 1200 to move in a direction in whichthe gap in the wedge-like space 1200 becomes larger, whereby the stopperbody 1300 is allowed to move relative to the guide member 1100 towardthe side at which the gap in the wedge-like space 1200 is larger.

As the release mechanism, various forms of ones can be adopted, but inthe following, reference will be made to those of a lever type, a platetype, a ring type, and an air type, from the form of an operation part.

Construction of Lever Type Release Mechanism

The schematic construction of a lever type release mechanism is shown inFIG. 2.

A stopper body 1300 has at least one pair of one-way stopper mechanisms1700L, 1700R with the directions of wedge-like spaces 1200 becomingmutually opposite to each other with respect to a guide member 1100, sothat the relative movement of the stopper body 1300 in the oppositedirections of the reciprocating movement thereof with respect to theguide member 1100 is able to be restricted.

In particular, a tapered surface 1210 of each of the one-way stoppermechanisms 1700L, 1700R is arranged in an axially central portion(center) of a through hole 1310 in the stopper body 1300, wherein thewedge-like spaces 1200 are each constructed with a gap which becomesgradually smaller toward its center, so that rolling elements 1400 arearranged in directions to bite toward a central side from axiallyopposite end sides (opposite sides), and are pushed by rolling elementpressing mechanisms 1500 in directions to bite into the wedge-likespaces 1200.

The lever type release mechanism 2100 is constructed such that it forcesthe rolling elements 1400 arranged in the wedge-like space 1200 of eachof the one-way stopper mechanisms 1700L, 1700R to move in a direction inwhich the gap in the wedge-like space 1200 becomes larger, i.e., in adirection from the center toward the side, whereby the rolling elements1400 are placed into an unclamped state with respect to the guide member1100, thus making possible the relative movement of the stopper body1300 in the axially opposite directions.

In the illustrated example, it is constructed such that an ellipticalcam 2110 is driven to rotate by a lever 2120, so that the retainers 1600for the rolling elements 1400 are caused to move in releasing directionsdue to a longer side cam surface of the elliptical cam 2110, or indirections to allow biting of the rolling elements due to a shorter sidecam surface of the elliptical cam 2110.

Plate Type Release Mechanism

FIG. 3 shows the schematic construction of a plate type releasemechanism 2200.

A stopper body 1300 has one-way stopper mechanisms 1700L, 1700R with thedirections of wedge-like spaces 1200 becoming mutually opposite to eachother with respect to a guide member 1100, so that the relative movementof the stopper body 1300 in the opposite directions of the reciprocatingmovement thereof with respect to the guide member 1100 is able to berestricted.

In this example, a tapered surface of each of the one-way stoppermechanisms 1700L is arranged in an axial end portion (side) of a throughhole 1310 in the stopper body 1300, wherein the wedge-like spaces 1200are each constructed with a gap becoming gradually smaller from itsaxially central portion (center) toward its opposite sides, so that therolling elements 1400 are arranged in directions to bite toward theopposite sides from the center, and are pushed by rolling elementpressing mechanisms 1500 in directions to bite into the wedge-likespaces 1200.

The release mechanism 2200 for the rolling elements 1400 is constructedsuch that it forces the rolling elements 1400 arranged in the wedge-likespace 1200 of each of the one-way stopper mechanisms 1700L, 1700R tomove in a direction in which the gap in the wedge-like space 1200becomes larger, i.e., in a direction from the side toward the center,whereby the rolling elements 1400 are placed into an undamped state withrespect to the guide member 1100, thus making possible the relativemovement of the stopper body 1300 in the axially opposite directions.

In the illustrated example, it is constructed such that plates 2210arranged on axially opposite end faces (side faces) of the stopper body1300 are driven to rotate in directions to move toward and away from theopposite end faces, respectively, so that each retainer 1600 is causedto move, by means of a protruded portion 2220 formed on each plate 2210,in a direction (i.e., toward the center side) to release the rollingelements 1400, thereby placing them in an unclamped state. Each plate2210 has its one end supported in a freely rocking manner on an end faceof the stopper body 1300, and its other end formed as a free end. Inaddition, when in a free state, each plate 2210 is held in an open stateby means of a spring member 2230.

Each plate 2210 is formed in its middle portion with a protruded portion2220 for pushing a retainer 1600, wherein the retainer 1600 is pushed inthrough the protruded portion 2220 against the pressing force of arolling element pressing mechanism 1500, i.e., a spring force in theillustrated example, whereby the rolling elements 1400 bitten or engagedinto a wedge-like space 1200 are forced to move, through the retainer1600, in a direction in which a gap in the wedge-like space 1200 becomeslarger (i.e., in a direction from the side toward the center).

By clipping and pushing in the plates 2210 at the opposite ends of thestopper body 1300, the one-way stop mechanisms 1700 L, 1700R at theopposite (left and right) sides can be released at once.

Ring Type Release Mechanism 2300

FIG. 4 shows the schematic construction of a linear stopper to which aring type release mechanism 2300 is applied (for detailed construction,refer to FIGS. 12 through 15).

A stopper body 1300 has at least one pair of one-way stopper mechanisms1700L, 1700R with the directions of wedge-like spaces 1200 becomingmutually opposite to each other with respect to a guide member 1100, sothat the relative movement of the stopper body 1300 in the oppositedirections of the reciprocating movement thereof with respect to theguide member 1100 is able to be restricted.

In particular, a tapered surface 1210 of each of the one-way stoppermechanisms 1700L, 1700R is arranged in an axially central portion(center) of a through hole 1310 in the stopper body 1300, wherein thewedge-like spaces 1200 are each constructed with a gap which becomesgradually smaller toward its center, so that rolling elements 1400 arearranged in directions to bite toward a central side from axiallyopposite end sides (opposite sides), and are pushed by rolling elementpressing mechanisms 1500 in directions to bite into the wedge-likespaces 1200.

The ring type release mechanism 2300 is constructed such that it forcesthe rolling elements 1400 arranged in the wedge-like space 1200 of eachof the one-way stopper mechanisms 1700L, 1700R to move in a direction inwhich the gap in the wedge-like space 1200 becomes larger, in adirection from the center toward the side, whereby the rolling elements1400 are placed into an unclamped state with respect to the guide member1100, thus making possible the relative movement of the stopper body1300 in the axially opposite directions.

In the illustrated example, the ring type release mechanism 2300 isprovided with: ring-shaped slide cams 2310 that are formed at opposedends (center-side ends) of the pair of retainers 1600, respectively, andmove in a hole axial direction together with rolling element cages,respectively; pins 2320 that are each inserted into between the opposedsurfaces of the slide cams 2310 from the outside of the stopper body1300 through a guide slit 1340 which is formed in the stopper body 1300so as to extend in a circumferential direction thereof, so that slidepins 2320 are in sliding contact with the cam surfaces 2311 of the slidecams 2310; and an operation ring 2330 to which an outer end of each pin2320 is fixedly secured, and which is fitted in a rotatable manner to anouter periphery of the stopper body 1300.

The cam surfaces 2311 of each slide cam 2310 are partially formed inthree places in the circumferential direction, and the pins 2320 arealso arranged in three places corresponding to these three cam surfaces2311, and the pin guide slits 1340 are also formed in three placesindependently from one another.

The cam surfaces 2311 of the slide cams 2310, with which the pins 2320are in sliding contact, are each formed of a slant or inclined surfacewhich extends in the circumferential direction in an inclined manner ata predetermined lead angle. One circumferential end of each cam surface2311 at its position closest to the center is at a clamp position, atwhich a corresponding pin 2320 is out of contact with the cam surface,and the rolling elements 1400 are in contact with the tapered surface1210 of a corresponding wedge-like space 1200. From this clamp position,each cam surface 2311 extends in an inclined manner so as to cross thelocus of the movement of a corresponding pin 2320, wherein by turningthe pin 2320, it is made into contact with the cam surface 2311, so thatthe cam surface 2311 is pushed in an axial direction from the center tothe side, whereby a corresponding retainer 1600 for the rolling elements1400 is caused to move to the side through the slide cam 2310, therebycausing the rolling elements 1400 to separate from the tapered surface1210 of a corresponding wedge-like space 1200.

The slide cams 2310 are allowed to move with respect to the stopper body1300 in the hole axial direction, but are restricted against relativemovement in the rotational direction.

Although in this example, the cam surfaces are formed at the retainerside, they may also instead be formed at the pin side.

Air Type Release Mechanism 2400

FIG. 5 shows the schematic construction of a linear stopper to which anair type release mechanism 2400 is applied.

A stopper body 1300 has at least one pair of one-way stopper mechanisms1700L, 1700R with the directions of wedge-like spaces 1200 becomingmutually opposite to each other with respect to a guide member 1100, sothat the relative movement of the stopper body 1300 in the oppositedirections of the reciprocating movement thereof with respect to theguide member 1100 is able to be restricted.

In particular, a tapered surface 1210 of each of the one-way stoppermechanisms 1700L, 1700R is arranged in an axially central portion(center) of a through hole 1310 in the stopper body 1300, wherein thewedge-like spaces 1200 are each constructed with a gap which becomesgradually smaller toward its center, so that rolling elements 1400 arearranged in directions to bite toward a central side from axiallyopposite end sides (opposite sides), and are pushed by rolling elementpressing mechanisms 1500 in directions to bite into the wedge-likespaces 1200.

This air type release mechanism 2400 is constructed such that it forcesthe rolling elements 1400 arranged in the wedge-like space 1200 of eachof the one-way stopper mechanisms 1700L, 1700R to move in a direction inwhich the gap in the wedge-like space 1200 becomes larger, i.e., in adirection from the center toward the side, whereby the rolling elements1400 are placed into an unclamped state with respect to the guide member1100, thus making possible the relative movement of the stopper body1300 in the axially opposite directions.

In the illustrated example, an annular stepped portion 2410 providedwith an air supply hole is formed in the center of the through hole 1310in the stopper body 1300, and a hollow air expansion and contractionmechanism 2400, which can be expanded and contracted in a hole axialdirection, is constructed between this annular stepped portion 2410 anda center-side end of a retainer 1600, wherein by means of this airexpansion and retraction mechanism 2400, the rolling elements 1400arranged in the wedge-like space 1200 of each of the one-way stoppermechanisms are forced to move in a direction in which the gap in thewedge-like space 1200 becomes larger, i.e., in a direction from thecenter toward the side, whereby the rolling elements 1400 are placedinto an unclamped state with respect to the guide member, thus makingpossible the relative movement of the stopper body 1300 in the axiallyopposite directions.

The air expansion and contraction mechanism 2400 is, for example, of asealed hollow annular structure, which has an inner peripheral wall andan outer peripheral wall formed of a bellows structure which can beexpanded and contracted in the hole axial direction, with their tip endsbeing in abutment with an end of the retainer 1600 which holds therolling elements. Then, by supplying air pressure to the interior of theair expansion and contraction mechanism 2400 from an air passage 2420formed in the stopper body 1300, the air expansion and contractionmechanism 2400 is caused to expand, so that the retainer 1600 is pushedtoward the side from the center, thereby moving the rolling elements1400 away from the tapered surface 1210 of the wedge-like space 1200.Although in the illustration, the rolling elements 1400 are shown asapart from the guide member, this is a schematic view and in actuality,dimensions are such that the rolling elements 1400 are in contact withthe guide member 1100.

FIG. 6 and FIG. 7 show a linear stopper according to a first embodimentof the present invention.

Basically, this is an example in which the plate type release mechanismshown in FIG. 3 has been applied to the linear stopper.

First, a roller applied to this linear stopper will be described by theuse of FIG. 8.

FIG. 8 shows the roller according to the embodiment of the presentinvention.

In this figure, reference numeral 1 denotes the roller as a whole, andthis roller 1 is interposed between a guide surface C1 of a first guidemember 210, which takes an arcuate convex shape, and a guide surface C2of a second guide member 220, which takes an arcuate concave shape andis in opposition to the guide surface C1. The guide surface C1 of thefirst guide member 210 and the guide surface C2 of the second guidemember 220 have the same center of curvature O, and are located onconcentric circles.

The roller 1 is provided with a central concave surface portion 3 ofwhich a cross sectional configuration cut by a surface passing through aroller central axis N is an arcuate concave shape, and which is incontact with the convex shaped guide surface C1 of the first guidemember 210; and end convex surface portions 5, 5 which continue to theaxially opposite sides of the central concave surface portion 3, and ofwhich a cross sectional configuration cut by a surface passing throughthe roller central axis N is an arcuate convex shape, and which is incontact with the concave shaped guide surface C2 of the second guidemember 220.

Assuming that an arcuate shape formed by cutting the central concavesurface portion 3 with a plane passing through the roller central axis Nis the central concave circular arc 31, a radius of curvature R3 of thiscentral concave circular arc 31 is set to be slightly larger than aradius of curvature R1 of the convex shaped guide surface C1, and hence,a contact portion M3 of the central concave circular arc 31 in contactwith the guide surface C1 geometrically becomes a point contact. Inactuality, the contact portion has a certain width, and becomes acontact structure which has a pressure pattern with a geometric contactpoint as a peak of contact pressure. The magnitude of this radius ofcurvature R3 is slightly larger than the radius R1 of the guide surfaceC1, so as to provide such partial contact. When the magnitude of thisradius of curvature R3 is set to be, for example, about 102% ortherearound of the radius R1 of the guide surface C1, a partial contactstructure can be obtained. Of course, this is not limited to 102%.

On the other hand, assuming that circular arcs which are formed bycutting the opposite end convex surface portions 5, 5 with a planepassing through the roller central axis N are the opposite end convexcircular arcs 51, 51, a radius of curvature R5 of each end concavecircular arc 51 is slightly smaller than a radius of curvature R2 of theconcave shaped guide surface C2, and hence, a contact portion M5 of eachend concave circular arc 51 in contact with the guide surface C2geometrically becomes a point contact. In actuality, the contact portionhas a certain width, and becomes a contact structure which has apressure pattern with a geometric contact point as a peak of contactpressure. The magnitude of this radius of curvature R5 is slightlysmaller than the radius R2 of the guide surface C2, so as to providesuch partial contact. The magnitude of this radius of curvature R5 isalso set in a suitable manner according to the diameter of rollers, themagnitude of pre-load, etc., but when the magnitude of the radius ofcurvature R5 is set to be, for example, about 98% or therearound of theradius R2 of the guide surface C2, a partial contact structure can beobtained. Of course, this is not limited to 98%.

In the present invention, a radius M3R of a contact portion M3 of thecentral concave surface portion 3 in contact with the guide surface C1of the first guide member 210 from the roller central axis N, and aradius M5 r of the opposite contact portions M5, M5 of the opposite endconvex surface portions 5, 5 in contact with the guide surface C2 of thesecond guide member 220 from the roller central axis N are set to thesame radius.

The contact portions M3, M5 are set as geometric contact points,respectively, and in the illustrated example, the contact portion M3 islocated at the axial midpoint position of the central concave surfaceportion 3, and is a minimum diameter portion of the central concavesurface portion 3. A radius center of curvature O3 becomes a position ata predetermined distance from the center of curvature O, as seen fromthe guide surface C1.

On the other hand, the contact portions M5, M5 of the opposite endconvex surface portions 5, 5 are located on a line N3 which passesthrough the contact portion M3 of the central concave surface portion 3and which is parallel to the roller central axis N, and the centers ofcurvature O5, O5 of the opposite end convex surface portions 5, 5 arelocated on normal lines which are orthogonal to tangent lines of thecontact portions M5, respectively. These centers of curvature O5, O5 aredeviated or shifted by a prescribed dimension δ with respect to anorthogonal line Q which passes through the center of curvature O of theguide surfaces C1, C2, and which is orthogonal to the roller centralaxis N, and are located at positions close to the center of curvature O,as seen from the guide surface O2.

Here, note that the lengths in the roller central axis direction of theright and left opposite end convex surface portions 5, 5 are set to thesame length in this embodiment, but they may be different lengths in theright and left, respectively.

Next, reference will be made to a linear stopper using rollers asreferred to above, with the use of FIG. 6 and FIG. 7.

That is, this linear stopper 201 is provided with a first stoppermechanism 210L and a second stopper mechanism 210R which are arranged inpair in the axial direction to form mutually oppositely directed one-waystopper mechanisms, and which can be mounted in a detachable manner on alinearly extending guide member 200 which serves to guide an object forfree reciprocating movement.

In the illustrated example, the guide member 200 is a rod-shaped memberof a circular cross section.

The first stopper mechanism 210R is of a construction including: astopper body 230 that has a flat inclined surface 221 formed thereon,with a wedge-like space 220 being constructed between the inclinedsurface 221 and a surface of the guide member 200 with a gap decreasinggradually toward one side (right direction in the illustration) of theextending direction of the guide member 200; rollers 1 of the presentinvention that are arranged in the wedge-like space 220 so as to berollable therein; and a pressing spring 250 acting as pressing meansthat presses the rollers 1 in a direction to bite into the wedge-likespace 220, so that the rollers 1 are forced into pressure contact withthe surface of the guide member 200 and the inclined surface 221 of thestopper body 230.

The stopper body 230 is composed of a cylindrical member of aquadrangular shape with a hole 231 of a circular cross section formedtherein, and has the above-mentioned inclined surface formed on an innersurface thereof in opposition to one side surface of the guide member200. The shape of the stopper body 230 is not limited to thequadrangular shape, but instead may also be a round shape or othershapes. In the illustrated example, the inclined surface 221 is atapered shape which inclines in a conular shape corresponding to theguide member 200. The inclined surface 221 may be linear, or may becurved.

The rollers 1 are held by means of a retainer 280.

The retainer 280 is composed of a cylindrical member which has retainingholes 281 formed therein for holding or retaining the rollers 1.

On the other hand, the pressing spring 250 is a coil spring, which hasone end engaged with a stepped portion of the stopper body 230 formed ata back or deep end thereof, and the other end engaged with an end of theretainer 280. The pressing spring 250 is not limited to the coil spring,but instead, other spring members such as a laminated spring, etc. canbe used.

Thus, it is constructed such that the relative movement of the stopperbody 230 with respect to the guide member 200 toward a side at which agap of the wedge-like space 220 is large is restricted due to a bitingaction caused by the rolling contact of the rollers 1 in the wedge-likespace 220, whereas the relative movement of the stopper body 230 withrespect to the guide member 200 toward a side at which the gap of thewedge-like space 220 is small is allowed due to the sliding contact ofthe rollers 1 in the wedge-like space 220.

On the other hand, the second stopper mechanism 210L is of aconstruction in which a wedge-like space 220 is arranged in mutuallyopposite directions to that of the first stopper 20L with respect to theguide member 200, wherein it is constructed such that the relativemovement of a stopper body 230 with respect to the guide member 200toward a side at which a gap of the wedge-like space 220 is large isrestricted due to a biting action caused by the rolling contact ofrollers 1 in the wedge-like space 220, whereas the relative movement ofthe stopper body 230 with respect to the guide member 200 toward a sideat which the gap of the wedge-like space 220 is small is allowed due tothe sliding contact of the rollers 1 in the wedge-like space 220.According to such a construction, it is possible to restrict therelative movement of the stopper body 230 with respect to the guidemember 200 to the opposite sides of the extending direction of the guidemember 200. Because the basic construction of the second stoppermechanism 210L is the same as that of the first stopper mechanism 210R,the same symbols are attached to the same component parts, and thedescription thereof is omitted.

In this example, the wedge-like spaces 220 of the first stoppermechanism 210LR and the second stopper mechanism 210L are arranged inthe central portion of the stopper body 230, so that their wide gapsides are in opposition to each other, whereas those sides of thewedge-like spaces 220 at which the gaps are wide are in mutuallyopposite directions, i.e., located at the central side of the stopperbody 230.

In addition, in this embodiment, release mechanisms 270 acting asrolling element release means are provided which serve to force therollers 1, 1 arranged in the wedge-like spaces 220, 220 of the firststopper mechanism 210R and the second stopper mechanism 210L to move indirections in which the gap in each wedge-like space 220 becomes larger,whereby the stopper body 230 is allowed to move relative to the guidemember 200 toward a side at which the gaps in the wedge-like spaces 220,220 are larger.

These release mechanisms 270 are constructed such that they areprovided, on the axially opposite end surfaces of the stopper body 230,with a first pressing plate and a second pressing plate 271R, 271L forreleasing the first stopper mechanism 210R and the second stoppermechanism 220L, respectively.

Referring to the first pressing plate 271R, an insertion hole throughwhich the guide member 200 is inserted is formed through the firstpressing plate 271R, and the first pressing plate 271R has one endsupported by the stopper body 230 for free rocking motion, and the otherend formed as a free end. In addition, when in a free state, the firstpressing plate 271R is held in an open state by means of a spring member272.

Then, a pressing head 273 for pushing the roller retainer of the firststopper mechanism 210R is formed on a middle portion of the firstpressing plate 271R, wherein by pushing in the roller retainer 280through the pressing head 273 against the spring force of the pressingspring 250, the individual rollers 1 arranged in the wedge-like space220 of the first stopper mechanism 210R are forced to move through theroller retainer 280 in a direction in which the gap in the wedge-likespace 220 becomes larger, so that they are caused to move with respectto the guide member 200 to a side in which the gap in the wedge-likespace 220 is large.

Referring to the second pressing plate 271L, too, it is one and the sameas the first pressing plate 271R, and an insertion hole through whichthe guide member 200 is inserted is formed through the second pressingplate 271L, and the second pressing plate 271L has one end supported bythe stopper body 230 for free rocking motion, and the other end formedas a free end. In addition, when in a free state, the second pressingplate 271L is held in an open state by means of a spring member 272.

Then, a pressing head 273 for pushing the roller retainer 280 of thesecond stopper mechanism 210L is formed on a middle portion of thesecond pressing plate 271L, wherein by pushing in the roller retainer280 through the pressing head 273 against the spring force of thepressing spring 250, the individual rollers 1 arranged in the wedge-likespace 220 of the second stopper mechanism 210L are forced to movethrough the roller retainer 280 in a direction in which the gap in thewedge-like space 220 becomes larger.

The first and second pressing plates 271R, 271L are arranged at theaxially opposite end sides of the stopper body 230, so that the firstand second stopper mechanisms 210R, 220L can be released at once bypinching the first and second pressing plates 271R, 271L with a hand orfingers and pushing them in.

With the linear stopper 201 of the above-mentioned construction, in astate where it is removed from the guide member 200, the rollerretainers 280 are engaged with the stepped portions of the stopper body230, respectively, so that the rollers 1 are supported by the stopperbody 230 through the roller retainers 280.

Then, in a state where the first and second pressing plates 271R, 271Lare pushed in the inner periphery of the stopper body 230 is caused tomove from one end of the guide member 200 up to an appropriate positionof the guide member 200. The roller retainers 280 of the first stoppermechanism 210R and the second stopper mechanism 210L are moved indirections to mutually approach by means of the pressing heads 273, withthe first and second pressing plates 271R, 271L being pushed in so theindividual rollers 1 of the first and second stopper mechanisms 210R,210L slide on the surface of the guide member 200, and move to theirpredetermined positions, without biting into the wedge-like spaces 220,220.

When the hand or fingers are removed from the first and second pressingmembers 271R, 271L, the individual roller retainers 280, 280 are urgedin directions to bite into the wedge-like spaces 220, 220 by means ofthe individual pressing springs 250, 250 of the first and second stoppermechanisms 210L, 210R, respectively, so that the rollers 1, 1 are pushedagainst the side surface of the guide member 200 and the inclinedsurfaces 221, 221 in the wedge-like spaces 220, 220, respectively.

In this state, even if the stopper body 230 is to be moved with respectto the guide member 200 to either side of the extending direction of theguide member 200, the rollers 1 in either of the first and secondstopper mechanisms 210L, 210R will bite into any of the wedge-likespaces 220 due to rolling contact therebetween, and the relativemovement of the stopper body 230 will be restricted.

In addition, contact pressure is increased due to the biting action ofthese rollers 1, 1, and hence, even if the contact surfaces between therollers and the guide member 200 and between the rollers and the stopperbody 230 are circular, the sliding of the rollers in the circumferentialdirection is restricted by the friction of contact, thus making itpossible to restrict the rotation of the rollers.

Then, in cases where the guide member 200 is caused to move again, bypushing in the first and second pressing plates 271R, 271L of therelease mechanisms 270, the biting of the rollers into the wedge-likespaces 220 is released, thus making it possible for the rollers to morefreely in either direction. Releasing of the rollers is easy because ofbiting of the rollers 1.

In addition, the wedge-like spaces of the first stopper mechanism 210Rand the second stopper mechanism 210L are arranged in such a manner thattheir wide gap sides are in opposition to each other in the centralportion of the stopper body 230, but on the contrary, they may alsoinstead be arranged in such a manner that those sides of the wedge-likespaces at which the gaps are narrow are in mutual opposition to eachother in the central portion of the stopper body 230. In that case,though not illustrated in particular, it may be a mechanism in which theretainers 280 can be pulled by pushing in the first and second pressingplates 271R, 271L, or other release mechanisms may be constructed.

Moreover, although in the above-mentioned embodiment, it is constructedsuch that movements of the guide member 200 to the opposite sides of theextending direction thereof are restricted, the construction may also besuch that only the movement of the guide member 200 to one side of theextending direction is restricted by means of only a one-way stopmechanism at one side.

FIG. 9 shows an example of a roller guide device using theabove-mentioned rollers 1.

As a conventional roller guide device using rollers, there has beenknown one as described in Japanese patent application laid-open No.S62-227532, for example. That is, the rollers acting as rolling elementsare interposed between a guide shaft in the form of a round shaft and abush, which is fitted over the guide shaft so as to be guided in alinear manner along the guide shaft.

For the rollers used for this roller guide device, there have been usedrollers of a special shape, each of which is provided with a centralconcave surface portion which is in contact with an outer peripheralsurface of the shaft, and end convex surface portions which extendtoward opposite end sides in the roller axial direction of this centralconcave surface portion, and are in line contact with an innerperipheral surface of the bush.

Although this roller provides a rolling guide mechanism of highrigidity, the roller of this special shape has a peripheral speeddifference between the central concave surface portion and the endconvex surface portions, so there has been a problem that differentialsliding or slipping occurs between the rolling contact surface of thecentral concave surface portion and the rolling contact surfaces of theend convex surface portions, thus giving rise to early wear due to thesliding.

The rollers of the present invention serve to eliminate the differentialsliding or slipping between the central concave surface portion and theend convex surface portions.

The roller guide device 100 of the present invention is constructed toinclude a circular guide shaft 110 of a limited slide type as a firstguide member that is provided with an arcuate guide surface, acylindrical body 120 as a second guide member that is provided with anarcuate guide surface 121 which is in opposition to the guide surface111 of this guide shaft 110 and which has a radius of curvature largerthan that of the guide surface 111 of the guide shaft 110, and rollers 1of the present invention that are interposed in a freely rollable mannerbetween the guide surface 111 of the guide shaft 110, and the guidesurface 121 of the cylindrical body 120.

These rollers 1 are held by a roller retainer 130, and the cylindricalbody 120 is freely movable relative to the guide shaft 110 through therollers The diameter of each roller 1 is made larger than the distanceor interval between the guide surfaces 111, 121, so that a preload isgiven to the rollers.

The rollers 1 are arranged in plurality in the axial direction and inthe circumferential direction. The arrangement of rollers in thecircumferential direction may be arranged in a plurality of rows at thesame phase or at mutually different phases in the axial direction. Inaddition, as for the arrangement of the rollers in the axial direction,too, the rollers may be arranged at the same phase in thecircumferential direction axial, but can be arranged at different phasesin the circumferential direction.

The roller retainer 130 is a cylindrical member, and is inserted in anannular space between the outer periphery of the guide shaft 110, andthe inner periphery of the cylindrical body 120, so that the rollers 1are held in a freely rotatable manner in retaining holes 131,respectively, formed in the roller retainer 130. The holding of therollers in these retaining holes 131 is to prevent the rollers 1 fromfalling off at the time when the roller retainer 130 is pulled out, andit is constructed such that the holding is carried out in such a manneras to hold the circumferential surfaces of the individual rollers 1.

The range of movement of the cylindrical body 120 is a range in whichthe cylindrical body 120 is held by the roller retainer 130. However, ifa recirculation passage(s) for the rollers is formed in the cylindricalbody 120, it will be possible to achieve an endless sliding type rollerguide.

The guide surface 111 of the guide shaft 110 is a cylindrical outerperipheral surface of the cylindrical guide shaft 110, and the guidesurface 121 of the cylindrical body 120 is a cylindrical innerperipheral surface of the cylindrical body 120.

It is constructed such that a circle which forms the cylinder of theguide surface 111 of this guide shaft 110 corresponds to a firstreference circle C1 of the rollers 1 which is shown in FIG. 1, and thata circle which forms the cylinder of the guide surface 121 of thecylindrical body 120 corresponds to a second reference circle C2 of therollers 1.

Accordingly, a prescribed amount of width around the contact portion M3of the central concave surface portion 3 of each roller 1 is in contactwith the guide surface 111 of the guide shaft 110, and a prescribedwidth around each of the contact portions M5 of the opposite end convexsurface portions 5 is in contact with the guide surface 121 of the innerperipheral surface of the cylindrical body 120.

Because the radii of both the contact portions M3, M5 of the centralconcave surface portion 3 and the opposite end convex surface portions 5from the roller central axis N are the same radius, the peripheralspeeds of these contact portions at the time of rolling of each rollerbecome the same, and a differential slide or slip therebetween is madesmall, so that the sliding wear of the guide surfaces 111, 121 of thecentral concave surface portion 3 and the opposite end convex surfaceportions 5 can be maintained to a minimum, thus making it possible toattain the extension of life span.

Here, note that the roller guide device is not limited to a cylindricalshape, but may be not only such a roller bush which is provided with acylindrical body and a guide shaft, but also such a structure in whichthe rollers of the present invention are interposed in a freely rollablemanner between a convex arcuate guide surface and a concave arcuateguide surface, of which the centers of curvature are the same.

Moreover, the rollers of the present invention are not limited toapplication to guide devices, but can be applied to various kinds ofdevices.

FIG. 10 and FIG. 11 show an example using the lever type releasemechanism illustrated in FIG. 2.

Lever Type Construction

A stopper body 1300 has at least one pair of one-way stopper mechanisms1700L, 1700R with the directions of wedge-like spaces 1200 becomingmutually opposite to each other with respect to a guide member 1100, sothat the relative movement of the stopper body 1300 in the oppositedirections of the reciprocating movement thereof with respect to theguide member 1100 is able to be restricted.

In particular, a tapered surface 1210 of each of the one-way stoppermechanisms 1700L, 1700R is arranged in an axially central portion(center) of a through hole 1310 in the stopper body 1300, wherein thewedge-like spaces 1200 are each constructed with a gap which becomesgradually smaller toward its center, so that rolling elements 1400 arearranged in directions to bite toward a central side from axiallyopposite end sides (opposite sides), and are pushed by rolling elementpressing mechanisms 1500 in directions to bite into the wedge-likespaces 1200.

The lever type release mechanism 2100 is constructed such that it forcesthe rolling elements 1400 arranged in the wedge-like space 1200 of eachof the one-way stopper mechanisms 1700L, 1700R to move in a direction inwhich the gap in the wedge-like space 1200 becomes larger, i.e., in adirection from the center toward the side, whereby the rolling elements1400 are placed into an unclamped state with respect to the guide member1100, thus making possible the relative movement of the stopper body1300 in the axially opposite directions.

In the illustrated example, it is constructed such that an ellipticalcam 2110 is driven to rotate by a lever 2120, so that the retainers 1600for the rolling elements 1400 are caused to move in releasing directionsdue to a longer side cam surface of the elliptical cam 2110, or indirections to allow biting of the rolling elements due to a shorter sidecam surface of the elliptical cam 2110.

The cam 2110 is arranged in pair on an axial line, which is orthogonalto the central axis of the guide member 1100, in a gap between the outerperiphery of the guide member 1100 and the inner periphery of thethrough hole in the stopper body, so as to be in opposition to eachother with respect to the central axis. Each cam is fixedly secured toan inner end of a rotation shaft supported for free rotation in abearing hole formed in a lever main body, and one end of the lever forrotating the rotation shaft is fixedly secured to an outer end of therotation shaft.

Each cam is rotatable between two positions, i.e., an unclamp positionin which a major or longer axis of the cam becomes parallel to thecentral axis of the guide member, and a clamp position in which thelonger axis becomes orthogonal to the central axis of the guide member,in an angular range of approximately 90 degrees. Each lever is urged, ina free state thereof, by means of a return spring so that it is locatedin the clamp position. In this clamp position, each cam is not incontact with the rolling element cages, and is in a position in which itcan not prevent biting of the rolling elements.

The levers extend in a direction orthogonal to the rotation shaft of thecams, and the levers on the opposite sides have their tip ends connectedwith each other by a connection bar, thus forming an inverted U shape asa whole.

In addition, the levers are held in the clamp positions by means of apair of torsion coil springs on opposite sides, which serve to alwaysurge the longer side cam surfaces in directions toward the clamppositions.

The stopper body is formed on its side surfaces with concave portionseach in the shape of a sector over the rotation range of the levers,wherein the levers rotate along the concave portions, respectively, andin the clamp positions, the levers are brought into abutment with theends of the concave portions by the urging forces of the return springs,respectively.

FIGS. 12 through FIG. 15 show a linear stopper using the ring typerelease mechanism illustrated in FIG. 4.

A stopper body 1300 has at least one pair of one-way stopper mechanisms1700L, 1700R with the directions of wedge-like spaces 1200 becomingmutually opposite to each other with respect to a guide member 1100, sothat the relative movement of the stopper body 1300 in the oppositedirections of the reciprocating movement thereof with respect to theguide member 1100 is able to be restricted.

In particular, a tapered surface 1210 of each of the one-way stoppermechanisms 1700L, 1700R is arranged in an axially central portion(center) of a through hole 1310 in the stopper body 1300, wherein thewedge-like spaces 1200 are each constructed with a gap which becomesgradually smaller toward its center, so that rolling elements 1400 arearranged in directions to bite toward a central side from axiallyopposite end sides (opposite sides), and are pushed by rolling elementpressing mechanisms 1500 in directions to bite into the wedge-likespaces 1200.

The ring type release mechanism 2300 is constructed such that it forcesthe rolling elements 1400 arranged in the wedge-like space 1200 of eachof the one-way stopper mechanisms 1700L, 1700R to move in a direction inwhich the gap in the wedge-like space 1200 becomes larger, i.e., in adirection from the center toward the side, whereby the rolling elements1400 are placed into an unclamped state with respect to the guide member1100, thus making possible the relative movement of the stopper body1300 in the axially opposite directions.

In the illustrated example, the ring type release mechanism 2300 isprovided with: ring-shaped slide cams 2310 that are formed at opposedends (center-side ends) of the pair of retainers 1600, respectively, andmove in a hole axial direction together with rolling element cages,respectively; pins 2320 that are each inserted into between the opposedsurfaces of the slide cams 2310 from the outside of the stopper body1300 through a guide slit 1340 which is formed in the stopper body 1300so as to extend in a circumferential direction thereof, so that slidepins 2320 are in sliding contact with the cam surfaces 2311 of the slidecams 2310; and an operation ring 2330 to which an outer end of each pin2320 is fixedly secured, and which is fitted in a rotatable manner to anouter periphery of the stopper body 1300.

In the illustrated example, the cam surfaces 2311 of each slide cam 2310are partially formed in three places in the circumferential direction,and the pins 2320 are also arranged in three places corresponding tothese three cam surfaces 2311, and the pin guide slits 1340 are alsoformed in three places independently from one another.

The cam surfaces 2311 of the slide cams 2310, with which the pins 2320are in sliding contact, are each formed of a slant or inclined surfacewhich extends in the circumferential direction in an inclined manner ata predetermined lead angle. One circumferential end of each cam surface2311 at its position closest to the center is at a clamp position, atwhich a corresponding pin 2320 is out of contact with the cam surface,and the rolling elements 1400 are in contact with the tapered surface1210 of a corresponding wedge-like space 1200. From this clamp position,each cam surface 2311 extends in an inclined manner so as to cross thelocus of the movement of a corresponding pin 2320, wherein by turningthe pin 2320, it is made into contact with the cam surface 2311, so thatthe cam surface 2311 is pushed in an axial direction from the center tothe side, whereby a corresponding retainer 1600 for the rolling elements1400 is caused to move to the side through the slide cam 2310, therebycausing the rolling elements 1400 to separate from the tapered surface1210 of a corresponding wedge-like space.

The slide cams 2310 are allowed to move with respect to the stopper body1300 in the hole axial direction, but are restricted against relativemovement in the rotational direction.

The stopper body 1300 is provided with a cylindrical body portion 1301,taper rings 1305 that form the tapered surfaces 1210, respectively,collars 1302 for fixing the taper rings 1305 with respect to the axialdirection, respectively, and guide bushes 1303 that are in slidingcontact with the guide member 1100. In addition, in the illustratedexample, a restriction ring 2350 is provided which serves to allow therelative movement of the slide cams in the hole axial direction but torestrict the relative movement of the slide cams in the rotationaldirection, with respect to the stopper body. This restriction ring 350is interposed between the outer peripheries of the slide cams 2310 andthe inner peripheral surface of the stopper body 1300, and is fixedlysecured to the stopper body 1300. It is constructed such that therestriction ring 2350 is formed with convex portions 2351 which are inengagement with restriction grooves 2313 formed in the slide cams 2310to extend in the hole axial direction, whereby the movements of theslide cams 2310 in the hole axial direction are allowed, but therelative movements thereof in the rotational direction are restricted.The restriction grooves 2313 are formed in three places in thecircumferential direction by making use of between the adjacent camsurfaces 2311, and the convex portions 2351 of the restriction ring 2350are also formed in three places in the circumferential direction.

FIG. 16 shows a schematic cross sectional view of a linear stopperaccording to another embodiment of the present invention.

That is, this linear stopper 1 is constructed such that a pair ofbidirectional stopper mechanisms are arranged with a guide member 100sandwiched therebetween, wherein each bidirectional stopper mechanism isprovided with a first stopper mechanism 10L and a second stoppermechanism 10R which are arranged in pair in the axial direction to formmutually oppositely directed one-way stopper mechanisms, and which canbe mounted in a detachable manner on a linearly extending guide member100 which serves to guide an object for free reciprocating movement.Because the individual bidirectional stopper mechanisms 10 are of thesame construction, one of the bidirectional stopper mechanisms 10 willbe described below.

In the illustrated example, the guide member 100 is a rod-shaped memberof a hexagonal cross section, and the first stopper mechanism 10L andthe second stopper mechanism 10R are mounted on two mutually oppositeside surfaces of the hexagonal guide member 100 in opposition to eachother. Although in this example, the guide member 100 has a hexagonalshape in cross section, it is not limited to the hexagonal shape, butmay instead be a triangle, a rectangle, pentagon, or a heptagonal orother polygonal shape. Also, it is not limited to polygonal shapes, butmay of course be a circular shape in cross section. In addition, theguide member 100 may not be a floated rail, but may instead be of a laiddown guide structure in which one side of a guide member is laid down.

The first stopper mechanism 10L, which is a one-way stop mechanismconstituting the bidirectional stopper mechanism 10, is of a structureincluding: a stopper body 30 that has a flat inclined surface 21 formedthereon, with a wedge-like space 20 being constructed between theinclined surface 21 and a surface of the guide member 100 with a gapdecreasing gradually toward one side (right direction in theillustration) of the extending direction of the guide member 100;rollers 40 acting as rolling elements that are arranged in thewedge-like space 20 so as to be rollable therein; and pressing springs50 acting as rolling element pressing means that press the rollers 40 ina direction to bite into the wedge-like space 20, so that the rollers 40are forced into pressure contact with the surface of the guide member100 and the inclined surface 21 of the stopper body 30.

The stopper body 30 is composed of a hollow cylindrical member of aquadrangular shape through which a hole 31 of a hexagonal shape incross-section is formed, and which has the above-mentioned inclinedsurface formed on an inner surface in opposition to one side surface ofthe guide member 100. In the illustrated example, the inclined surface21 takes a shape curved in a concave shape with respect to the guidemember 100. However, the inclined surface 21 may be linear, or in somecases, may be curved in a convex shape.

This stopper body 30 may have a two-piece construction formed of a firsthalf body 30A and a second half body 30B, which are fixedly fastened toeach other by means of bolts, as shown in FIG. 2.

On the other hand, the rollers 40 are held by means of a retainer 80.The retainer 80 is composed of a plate-like member of a quadrangularshape which has retaining holes 81 formed therein for holding orretaining the rollers 40. The retaining holes 81 each have front andrear end edges 81 a formed into an arcuate shape conforming to thecurvature of each roller 40, so that the rollers 40 are held in theretaining holes 81 by the front and rear end edges 81 a thereof.

On the other hand, the retainer 80 has its right and left side endsengaged with guide grooves 32, respectively, formed in an inner surfaceof the inner periphery of the stopper body 30, wherein when the stopperbody 30 is pulled out from the guide member 100, the retainer 80 is heldin the guide grooves 32, and the rollers 40 are supported by the stopperbody 30 through the retainer 80. The width of each guide groove 32 islarger than the thickness of the retainer 80, and when the retainer 80is assembled or engaged into the guide grooves 32, the ends of theretainer 80 come Into contact with the side surfaces of the guide member100.

In addition, the pressing springs 50 are coil springs, each of which hasone end engaged with a spring retaining plate 90 fixedly attached to oneend face of the stopper body 30, and the other end engaged with a convexportion 32 formed on one end of the retainer 80, which becomes a springseat.

Thus, it is constructed such that the relative movement of the stopperbody 30 with respect to the guide member 100 toward a side (L) at whicha gap of the wedge-like space 20 is large is restricted due to a bitingaction caused by the rolling contact of the rollers 40 in the wedge-likespace 20, whereas the relative movement of the stopper body 30 withrespect to the guide member 100 toward a side (R) at which the gap ofthe wedge-like space 20 is small is allowed due to the sliding contactof the rollers 40 in the wedge-like space 20.

Moreover, the stopper body 30 is provided with a reaction force supportpart which is in engagement with the guide member 100 to support areaction force acting on the inclined surface 21 from the rollers 40upon biting thereof into the wedge-like space 20 at the time ofrestriction of the relative movement of the stopper body 30. In thisexample, as shown in FIG. 1(B), the guide member 100 has a hexagonalshape in cross section, and inner surfaces 304, 305 of the hole 31,which are in engagement with side surfaces 104, 105 apart throughadjoining side surfaces 102, 103 from a side surface 101 which forms thewedge-like space, become a pressure support part.

On the other hand, the second stopper mechanism 10R, which constitutesthe bidirectional stopper mechanism 10, is of a construction in which awedge-like space 20 is arranged in mutually opposite directions to thatof the first stopper 10L with respect to of the guide member 100,wherein it is constructed such that the relative movement of a stopperbody 30 with respect to the guide member 100 toward a side (R) at whicha gap of the wedge-like space 20 is large is restricted due to a bitingaction caused by the rolling contact of rollers 40 in the wedge-likespace 20, whereas the relative movement of the stopper body 30 withrespect to the guide member 100 toward a side (L) at which the gap ofthe wedge-like space 20 is small is allowed due to the sliding contactof the rollers 40 in the wedge-like space 20. According to such aconstruction, it is possible to restrict the relative movement of thestopper body 30 with respect to the guide member 100 to the oppositesides of the extending direction of the guide member 100. Because thebasic construction of the second stopper mechanism 10R is the same asthat of the first stopper mechanism 10L, the same symbols are attachedto the same component parts, and the description thereof is omitted.

In this example, the wedge-like spaces 20 of the first stopper mechanism10L and the second stopper mechanism 10R are arranged in the centralportion of the stopper body 30, so that their narrow gap sides are inopposition to each other, whereas those sides of the wedge-like spaces20 at which the gaps are wide are in mutually opposite directions, i.e.,located at the end sides of the stopper body 30.

In addition, in this embodiment, release mechanisms 70 acting as rollingelement release means are provided which serve to force the rollers 40,40 arranged in the wedge-like spaces 20, 20 of the first stoppermechanism 10R and the second stopper mechanism 10L to move in directionsin which the gap in each wedge-like space 20 becomes larger, whereby thestopper body 30 is allowed to move relative to the guide member 100toward a side at which the gaps in the wedge-like spaces 20, 20 arelarger.

These release mechanisms 70 are each of a construction including apressing member 71 that is arranged to be insertable and removable fromthe outside of the stopper body 30 in a direction orthogonal to theextending direction of the guide member 100, and a spring 72 that urgesthe pressing member 71 in a direction to move away from the stopper body30. The pressing member 71 is formed at its inner tip end with apressing head 73 which is movable toward and away from the individualroller retainers of the first stopper mechanism 10R and the secondstopper mechanism 10L, respectively, and the pressing member 71 isformed at its outer end with a button part 74 for pressing it down witha finger. A connection pin connecting the button part 74 and thepressing head 73 with each other is inserted in a pin hole formed in thestopper body 30.

The pressing head 73 has a conical shape inclined or tapered to becomethinner toward its tip, with its inclined or tapered surface being inabutment with the individual roller retainers 80 of the first stoppermechanism 10R and the second stopper mechanism 10L, wherein by pushingin the pressing member 71 against the spring force of the spring 72, theroller retainers 80 are forced to move in directions away from eachother, i.e., the individual rollers 40 arranged in the wedge-like spaces20, 20 of the first and second stopper mechanisms 10L, 10R are forced tomove in directions in which the gaps in the wedge-like spaces 20, 20become larger, whereby it is made possible for the stopper body 30 tomove with respect to the guide member 100 to a side at which the gap ineither of the wedge-like spaces 20, 20 becomes larger, i.e., in thisexample, to the opposite sides of the extending direction of the guidemember 100.

With the linear stopper 1 of the above-mentioned construction, in astate where it is removed from the guide member 100, the rollerretainers 80 are engaged with the guide grooves 32 in the stopper body30, respectively, so that the rollers 40 are supported by the stopperbody 30 through the roller retainers 80.

Then, in a state where the pressing members 71 are pushed in, the innerperiphery of the stopper body 30 is caused to move from one end of theguide member 100 up to an appropriate position of the guide member 100.The roller retainers 80 of the first stopper mechanism 10L and thesecond stopper mechanism 10R are moved in directions mutually away fromeach other by means of the pressing heads 73, with the pressing members71 being pushed in, so that the individual rollers 40 in the first andsecond stopper mechanisms 10L, 10R slide on the surface of the guidemember 100, and move to their predetermined positions, without bitinginto the wedge-like spaces 20, 20.

When a hand is removed from each pressing member 71, the individualroller retainers 80, 80 are urged in directions to bite into thewedge-like spaces 20, 20 by means of the individual pressing springs 50,50 of the first and second stopper mechanisms 10L, 10R, respectively, sothat the rollers 40, 40 are pushed against the side surface of the guidemember 100 and the inclined surfaces 21, 21 in the wedge-like spaces 20,20, respectively.

In this state, even if the stopper body 30 is to be moved with respectto the guide member 100 in either side of the extending direction of theguide member 100, the rollers 40 in either of the first and secondstopper mechanisms 10L, 10R will bite into any of the wedge-like spaces20 due to rolling contact therebetween, and the relative movement of thestopper body 30 will be restricted.

Then, in cases where the guide member 200 is caused to move again, bypushing in the pressing members 71 of the release mechanisms 70, thebiting of the rollers into the wedge-like spaces 20 is released, thusmaking it possible for the rollers to move freely in either direction.Releasing of the rollers is easy because of biting of the rollers 40.

Here, note that there has been shown, by way of example, a case in whichcylindrical rollers are used as the rolling elements used for theabove-mentioned linear stopper, balls may instead be used, and in caseswhere the present invention is applied to a rail of a circular crosssection as a guide member, rollers in the shape of a barrel may be used,and thus, the shape of the rolling elements is not limited.

In addition, although in the above-mentioned embodiments, the firststopper mechanism 10L and the second stopper mechanism 10R are arrangedin the same phase in the circumferential direction, the phases in thecircumferential direction of the first stopper mechanism 10R and thesecond stopper mechanism 10R may be different from each other.

Moreover, although in the above-mentioned embodiments, a reaction forceacting on the inclined surfaces 21 of the stopper body 30 from therolling elements is supported by the inner surface of the stopper bodyin contact with the side surface of the guide member 100, but instead, areaction force of one of the bidirectional stopper mechanisms at oneside can be supported by the other bidirectional stopper mechanismlocated at an opposed side of the guide member, so that thebidirectional stopper mechanisms themselves may serve as reaction forcesupport parts.

In addition, the wedge-like spaces of the first stopper mechanism 10Rand the second stopper mechanism 10L are arranged in such a manner thattheir narrow gap sides are in opposition to each other in the centralportion of the stopper body 30, but on the contrary, they may alsoinstead be arranged in such a manner that those sides of the wedge-likespaces at which the gaps are wide are in mutual opposition to each otherin the central portion of the stopper body 30.

Moreover, although in the above-mentioned embodiment, it is constructedsuch that movements of the guide member 100 to the opposite sides of theextending direction thereof are restricted, the construction may alsoinstead be such that only the movement of the guide member 100 to oneside of the extending direction is restricted by means of only a one-waystop mechanism at one side.

EXPLANATION OF REFERENCE NUMERALS AND CHARACTERS

-   1 linear stopper-   10 bidirectional stopper mechanism-   10L first stopper mechanism-   10R second stopper mechanism-   20 wedge-like spaces-   21 inclined surfaces-   30 stopper body-   30A half body-   30B half body-   31 holes-   32 guide grooves-   40 rollers-   70 release mechanisms-   71 pressing members-   72 springs-   73 pressing heads-   74 button parts-   80 roller retainers-   81 retaining holes-   81 a front and rear end edges-   90 pressing plates-   100 guide member-   101,102, 103, 104, 105 side surfaces-   304, 305 inner surfaces (reaction force support parts)

What is claimed:
 1. A roller guide device comprising: a first guidemember that is provided with an arcuate guide surface, a second guidemember that is provided with an arcuate guide surface which is inopposition to the arcuate guide surface of the first guide member andwhich has a radius of curvature larger than that of the arcuate guidesurface of the first guide member, and rollers that are interposed in afreely rollable manner between the arcuate guide surface of the firstguide member, and the arcuate guide surface of the second guide member,wherein each roller is provided with a central concave surface portionof which a cross sectional configuration cut by a surface passingthrough a roller central axis is an arcuate concave shape, and which isin contact with the arcuate guide surface of the first guide member; andend convex surface portions which continue to the axially opposite sidesof the central concave surface portion, and of which a cross sectionalconfiguration cut by a surface passing through the roller central axisis an arcuate convex shape, and which is in contact with the arcuateguide surface of the second guide member, wherein a radius of a contactportion of the central concave surface portion in contact with the firstguide member from the roller central axis, and a radius of a contactportions of the opposite end convex surface portions in contact with thesecond guide member from the roller central axis are set to the sameradius.
 2. A roller guide device as set forth in claim 1, wherein,assuming that an: arcuate shape formed by cutting the central concavesurface portion with a plane passing through the roller central axis isthe central concave circular arc, a radius of curvature from a radiuscenter of curvature of this central concave circular arc is set to beslightly larger than a radius of curvature from a radius center ofcurvature of the convex shaped guide surface of the first guide memberand a radius center of curvature of the central concave circular arcbecomes a position at a predetermined distance from the center ofcurvature of the convex shaped guide surface of the first guide member,so as to provide such partial contact; and assuming that circular arcswhich are formed by cutting the opposite end convex surface portionswith a plane passing through the roller central axis are the oppositeend convex circular arcs, a radius of curvature from a radius center ofcurvature of each end concave circular arc is slightly smaller than aradius of curvature from a radius center of curvature of the concaveshaped guide surface of the second guide member, so as to provide suchpartial contact, and the centers of curvature of the opposite end convexcircular arcs are deviated or shifted by a prescribed dimension withrespect to an orthogonal line which passes through the center ofcurvature of the guide surfaces of the second guide member, and which isorthogonal to the roller central axis.
 3. A roller comprising: a centralconcave surface portion and end convex surface portions, a crosssectional configuration cut by a surface passing through a rollercentral axis of the central concave surface portion is an arcuateconcave shape, the end convex surface portions continue to the axiallyopposite sides of the central concave surface portion, and of which across sectional configuration cut by a surface passing through theroller central axis is an arcuate convex shape, wherein a radius of anaxial midpoint position of the central concave surface portion from theroller central axis, and a radius of axial intermediate positions of theopposite end convex surface portions from the roller central axis areset to the same radius.